Can Not Lock When Using The Rear Lock Button

WARNING: This page is about a different car, the 2016 Subaru Outback and 2016 Subaru Legacy. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION:

Check that there are no other registered access keys inside the vehicle.
Check that the keyless access function is not stopped.
Inspect LAN system or keyless access system according to the basic diagnostic procedure, and make sure that DTC is not input.
When the access key or keyless access control module is replaced, registration of the immobilizer is required. For the relevant procedures, refer to the "REGISTRATION MANUAL FOR IMMOBILIZER" provided as a separate volume.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK REAR GATE ACTUATOR. While carrying the access key, operate the touch sensor (lock) and touch sensor (unlock).	When the switch is operated, does the rear gate lock/unlock?	Go to step 2 .	Go to step 9 .
2 CHECK REAR LOCK BUTTON. Display the current data «Rear Gate Request SW» of «Keyless access with push button start» using Subaru Select Monitor. < Ref. to READ CURRENT DATA . > Read the data when operating the rear lock button.	Does the data change between ON/OFF?	Go to step 7 .	Go to step 3 .
3 CHECK HARNESS. Disconnect the rear lock button connector and the keyless access control module connector. Using a tester, measure the resistance between harness. Connector & terminal (D77) No. 3 - (i241) No. 24:	Is the resistance less than 10 Ω?	Go to step 4 .	Repair or replace the open circuit of the harness.
4 CHECK HARNESS. Using a tester, measure the resistance between harness and chassis ground. Connector & terminal (D77) No. 3 - Chassis ground:	Is the resistance 10 MΩ or more?	Go to step 5 .	Repair or replace the short of harness.
5 CHECK HARNESS. Using a tester, measure the resistance between harness and chassis ground. Connector & terminal (D77) No. 4 - Chassis ground:	Is the resistance less than 10 Ω?	Go to step 6 .	Repair or replace the open circuit of the harness.
6 CHECK REAR LOCK BUTTON. Measure the resistance when the rear lock button is operated using the tester. Connector & terminal (D77) No. 3 - No. 4:	Did the resistance change from 1 MΩ or more to less than 10 Ω?	Replace the keyless access control module. < Ref. to REMOVAL , Keyless Access control module. >	Replace the rear lock button. < Ref. to REMOVAL , Rear Lock Button. >
7 CHECK WIRING HARNESS. Disconnect the exterior rear antenna connector and the keyless access control module connector. Using a tester, check continuity between the exterior rear antenna connector and keyless access control module connector. Connector & terminal (D45) No. 1 - (i241) No. 16: (D45) No. 3 - (i241) No. 15:	Is there continuity?	Go to step 8 .	Repair or replace the open circuit of harness.
8 CHECK OUTSIDE REAR ANTENNA. Replace the outside rear antenna with new or properly working parts. < Ref. to REMOVAL , Keyless Access Outdoor Antenna. >	Does it operate properly?	The outside rear antenna has a failure.	Go to step 9 .
9 CHECK BODY INTEGRATED UNIT. Connect the disconnected connectors. Use the Subaru Select Monitor to perform the body integrated unit function check. < Ref. to FUNCTION CHECK . > Actuate the door lock actuator LOCK output.	Does the rear gate lock actuator lock?	It is possible that temporary poor communication occurs.	Go to step 10 .
10 CHECK HARNESS. Disconnect the body integrated unit connector and rear gate lock actuator connector. Check the continuity between body integrated unit connector and rear gate lock actuator connector. Connector & terminal (i266) No. 7 - (D46) No. 1:	Is there continuity?	Go to step 11 .	Repair or replace the open circuit of harness.
11 CHECK HARNESS. Check the continuity between the rear gate lock actuator connector and chassis ground. Connector & terminal (D46) No. 2 - Chassis ground:	Is there continuity?	Go to step 12 .	Repair or replace the open circuit of harness.
12 CHECK REAR GATE LOCK ACTUATOR. Check the rear gate lock actuator. < Ref. to INSPECTION , Rear Gate Latch and Actuator Assembly. >	Is the rear gate lock actuator normal?	Replace the body integrated unit. < Ref. to BODY INTEGRATED UNIT . >	Replace the rear gate latch and actuator assembly. < Ref. to REAR GATE LATCH AND ACTUATOR ASSEMBLY . >